David,
One possibility is to get rid of the ButtonFrame which seems to block
the GridBox option ColumnAlignments. Then you can embellish the gridbox
with a frame and use StyleBox to give it a background color. For
example
CellPrint[Cell[BoxData[StyleBox[GridBox[{{ButtonBox["this is text",
ButtonFrame -> "None"]}}, ColumnWidths -> 20, ColumnAlignments ->
Left, GridFrame -> True], Background -> GrayLevel[0.9]]], "Text",
FontWeight -> "Bold ", FontFamily -> "Helvetica"]]
Cheers,
Brian